This R34 responds to program announcement: Formative and Pilot Intervention Research for Prevention and Treatment of HIV/AIDS (PA-17-166). Over half of persons living with HIV (PLWH) worldwide are undiagnosed. To increase the number of PLWH who are aware of their status, the World Health Organization recommends that all PLWH receive assistance to notify their at-risk sex and needle-sharing partners so they can be offered HIV testing. A main limitation of these HIV prevention recommendations is the lack of evidence for implementing partner services in prisons and other criminal justice settings where HIV is frequently diagnosed. To increase HIV testing among at- risk partners, we will conduct research in Indonesia, where up to 14% of prisoners are HIV-infected, to achieve our specific aims which are to: 1) finalize a nurse-led partner notification intervention, IMPART, that we developed for the Indonesian prison setting, and 2) pilot IMPART for feasibility and acceptability through a clinical trail conducted in Jakarta's two largest prisons. To prepare for implementation, we will first conduct focus groups with 32 nurses (Phase 1) to examine individual provider-level barriers that may influence nurses' readiness to conduct partner elicitation, notification, HIV testing, and treatment referral. We will use these findings to finalize our intervention and training protocols in collaboration with a community advisory board and content experts and pre-test IMPART with 5 HIV- positive prisoners. In Phase 2, we will conduct a 2-arm pilot randomized controlled trial with 60 incarcerated index patients and their sex and needle-sharing partners in the community. Participants in the Choice arm may choose nurse provider-assistance (IMPART) to notify one or more partners, while those in the Control arm will be encouraged to notify their partner(s) themselves. Index patients in both groups will complete questionnaires before and after the intervention to assess HIV stigma and related psychosocial process that may influence disclosure. IMPART's acceptability will be assessed as the number of index patients who enroll or choose provider assistance, and the number of at-risk partners named. Feasibility will be assessed as the quality and completeness of partner locator information and barriers to partner notification and HIV testing encountered in the study. Finally, we will compare the number of partners in each arm who are: notified, HIV tested, newly diagnosed, and entering treatment. Structured interviews with HIV-positive partners 2 weeks after notification will provide additional information about IMPART's acceptability. The intervention and study design are products of a highly-qualified and interdisciplinary investigative team with extensive research experience in the Indonesian prison setting. Findings will supply essential information for a planned comparative effectiveness (R01) study of the IMPART intervention. If successful, this study will lead to a replicable evidence-informed model for HIV prevention in countries where HIV prevalence is high in prisoners. By developing an intervention to increase HIV testing and treatment in sex and drug use partners of HIV-positive prisoners, this study directly addresses NIH High Priority topics of research for support using AIDS-designated funds, and is consistent with the NIH Office of Women's Health Research Priorities for 2010-2020.